In known compression devices or compressor devices, it is customary to cool the compressor chamber and for this purpose to provide a cooling chamber which adjoins the compressor chamber. Thus, in known compressor devices with a common pressure casing for drive and compressor it is known to provide a comparatively thin partition for separating a compressor medium in the compressor chamber from the cooling medium in the adjoining cooling chamber. This partition can be a tube, for example, which is to be provided in a compressor device between its electric stator and the rotor. Such a tube should be designed as thin as possible for achieving the desired electrical functionality. Such a thin-walled tube, however, is limited in its pressure stability so that any hazard potential with regard to the existing pressure situation between compressor chamber and cooling chamber has to be excluded.
So that operation can be carried out with comparatively thin-walled tubes, even in the case of high compressor pressures, it is known to hold the pressure of the cooling medium, by means of a piston accumulator, lower than or equal to the compressor pressure. A system of this type, as is known for example from EP 1 482 179 B1, is very costly to adjust, however, and can possibly be seriously impaired in its function as a result of an inclusion of gases, such as air, in the media.
A multiphase pump for undersea operation is already known from WO 98/53182, in which a pressure compensating system ensures a positive pressure drop between a lubricating and cooling fluid and the process medium, wherein the driving electric motor is separated from the delivery pump by means of a shaft seal and the drive-side volume is filled completely with the lubricating and cooling fluid. WO 00/73621 A1, WO 2007/055589 A1, WO 2005/003512 A1, U.S. Pat. No. 2,423,436, and EP 0 550 381 A1 also deal with pumps or compressors which have a drive which is separated from the fluid flow unit by means of a seal so that the process fluid which is to be delivered does not come into contact with the drive. Such seals are expensive, especially with high demands for leak tightness. A compressor unit, in which a stator of an electric drive is separated from a compressor chamber by means of a cylindrical partition, is known from WO 2007/110281 A1. The strength requirements for such a partition are hard to fulfill, especially at a high pressure level, by means of conventional materials which also fulfill the requirement profile with regard to behavior in the electrical field and to chemical resistance.